The Guangdong provincial government has vowed to crack down on illicit mining of river sand, a senior water official said.

"We have had achievements in regulating river sand mining in the past few years, but illicit mining continues despite harsh punishments," Huang Boqing, director of the provincial water resources department, said at a news conference on Tuesday.

"The demand for river sand in Guangdong's market still far exceeds the supply. Those engaged in illicit river sand mining can make a very good profit," Huang said.